I recently opening up a bathroom wall to install framing and moving plumbing for a new hanging vanity. I unexpectedly discovered that the wall was actually many layers of walls on top of eachother. Because the bathroom is so narrow, I would like to reclaim as much of this new space as possible.
However, the current tile floor has larger gaps away from the wall at certain positions, like it was installed around or later cut away from some bathroom vanity that no longer exists. The gap is about 1/2" to 1" further from the wall than the uncut sections.
I'm looking for recommendations on how I can fill this gap that does not require placing tile. Most of these areas will be under the new vanity, or back behind a toilet, so it doesn't need to look perfect. Would something like a narrow strip of PVC board of the right thickness, with the joint filled with caulk be reasonable?